Closure plug



L T. KNOCKE CLOSURE PLUG Aug. 30, 1966 5 Sheets-Sheet 5 Filed Sept. 22, 1965 INVENTOR. Jazzzls 7, Aimc%c United States Patent "ice 3,269,582 CLOSURE PLUG Louis T. Knocke, 5578 Putnam, Birmingham, Mich. Filed Sept. 22, 1965, Ser. No. 489,370 3 Claims. (Cl. 220-245) This application is a continuation-in-part of application Serial No. 221,595, filed September 5, 1962, by the present applicant. This invention relates to closure plugs and tools therefor and, more particularly, to closure members which will fit tightly into a bore or other opening, forming a leakproof seal therewith.

It is an object of the invention to provide a novel and improved expansible type of closure plug which can be manufactured with extreme economy and is easily insertable into the bore to be sealed without damaging the bore or the sealing edge of the plug.

It is another object to provide an improved closure plug of this nature which incorporates an inherent sealing action enhanced by pressure exerted on the plug from within the bore.

It is another object to provide an improved closure plug of this type and a tool for assemblying the plug into a bore, the combination of closure plug and tool permitting alignment of the parts in a simple manner.

Other objects, features, and advantages of the present invention will become apparent from the subsequent description, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a cross-sectional view in elevation of one form of the closure plug;

FIGURE 2 is a cross-sectional view in elevation of the closure plug shown at the entrance to a bore, together with a suitable embodiment of the tool used for assembly.

FIGURE 3 is a cross-sectional view in elevation of a modified form of the closure plug;

FIGURE 4 is a cross-sectional view in elevation of a modified form of the assembly tool shown in conjunction with the plug of FIGURE 3;

FIGURE 5 is a cross-sectional view in elevation of a still further modification of the assembly tool;

FIGURE 6 is a cross-sectional view in elevation of a still further modification of the closure plug;

FIGURE 7 is a cross-sectional view in elevation of a further modified form of the closure plug;

FIGURE 8 is a cross-sectional view in elevation of a further embodiment of the closure plug which differs from those of FIGURES 1, 3, 6 and 7 in that a portion of the inwardly facing surface rather than the edge surface portion of the plug engages the flared entrance;

FIGURE 9 is a cross-sectional view in elevation of a modified form of the closure plug shown in FIGURE 8;

FIGURE 10 is a cross-sectional view in elevation of another modified form of the closure plug; and

FIGURE 11 is a cross-sectional view of the closure plug illustrated in FIGURE 10, as seen in operative association with an assembly tool therefor.

Briefly, the illustrated embodiments of the invention each comprises a closure plug fabricated from a circular disc of resiliently deformable metal or other material having an inwardly facing surface adapted to face the interior of a bore and an outwardly facing surface adapted to face a flared entrance to said bore when the plug is installed. The closure plug may be regarded as having a central inner zone, an intermediate zone surrounding the inner zone, and an outer zone surrounding the intermediate zone. All portions of the inner zone are on the side toward the bore interior of an imaginary plane intersecting the outwardly facing surface at the juncture of the inner and intermediate zones. An annular edge surface portion extends continuously between and connects the outer 3,269,582 Patented August 30, 1966 edges of the inwardly and outwardly facing surfaces. The inwardly facing surface has a portion in the outer Zone. The outer zone is so inclined that one of the two aforementioned surface portions is substantially at the same angle as and is engageable with the flared entrance to the bore. The intermediate zone is curved and connects the inner and outer zones in a continuous manner.

The inner zone may be flat or convex toward the bore interior. The intermediate zone in some embodiments is concave toward the bore interior, in which case the outer edge of the outwardly facing surface has a larger diameter than the outer edge of the inwardly facing surface, and the edge surface portion is engageable with the flared entrance. The intermediate zone in other embodiments is convex toward the bore interior, in which case the outer edge of the inwardly facing surface has a larger diameter than the outer edge of the outwardly facing surface, and the surface portion of the inwardly facing surface located in the outer zone is engageable with the flared entrance. In all embodiments, the outer edge having the larger diameter is relatively sharp and has an included angle sufficiently great to prevent substantial deformation of the outer edge when the plug is inserted in the bore by application of an axial force at the center of the plug.

The tool for assembling the plug in the bore comprises a sleeve element and a plunger element, the plunger element having one end engageable with the plug, this end being of greater convexity than any concavity of the outwardly facing central zone surface when the plug is unstressed. Means are provided on one of the two elements for aligning the tool with the bore. In cases where the flared entrance is integral with the bore, this means may comprise a bearing surface on the sleeve engageable with the intermediate plug zone, or a portion on the plunger element having substantially the same diameter as the bore and insertable therein before the plug is placed in position. In cases Where the flared entrance is integral with the sleeve, the aligning means comprises a portion on the plunger having substantially the same diameter as and insertable within the bore.

'Referring more particularly to the drawings, a first form of the closure plug is shown in FIGURE 1 and is generally indicated at 11. Plug 11 is fabricated from a circular disc'of resiliently deformable material and has an inwardly directed surface 12 and an outwardly directed surface 13 when the plug is installed in bore 15 within a part 16. Bore 15 may, for example, hold a bearing (not shown) for which lubricant under pressure is supplied, the plug being adapted to seal the pressurized lubricant within the bore. Part 16 is provided with an outwardly flared entrance 17 at the mouth of the bore.

Closure plug 11 has a central inner zone 18 occupying the major portion of the plug, an intermediate zone 19 surrounding zone 18, and an outer zone 21 surrounding zone 19. Zone 18 is entirely on the side toward bore 15 of an imaginary plane 22 intersecting outwardly facing surface 13 at the juncture of zones 18 and 19. More particularly, zone 18 is convex toward bore 1 5.

An edge surface portion 23 is provided between outer edge 24 of inwardly facing surface 12 and outer edge 25 of outwardly facing surface 13. Surface portion 23 extends continuously between edges 24 and 25, preferably at right angles to surfaces 12 and 13 at edges 24 and 25. Zone 21 is inclined in such manner that surface portion 23 is at approximately the same angle as flared entrance 17 of bore 15. The diameter of plug 11 in its unstressed condition is such that surface portion 23 is engageable with flared entrance 17. Outer edge 25 of surface 13 therefore has a larger diameter than outer edge 24 of surface 12. Edge 25 is relatively sharp and its included angle (in this case about is sufficiently great to prevent substantial deformation of edge 25 when plug 11 is inserted in bore 15 as described below.

A tool generally indicated at 26 is provided for inserting plug 11 in bore 15. This tool includes a sleeve element 27 and a plunger element 28. A bearing surface 29 is provided at the lower end of sleeve element 27, 7

this surface being engageable with at least a portion of intermediate zone 19 and a portion of zone 21 of closure plug 11. If closure plug 11 is in engagement with flared entrance 17 of bore 15, engagement of surface 29 with closure plug 11 will thus center tool 26 with respect to the bore.

Plunger element 28 is slidable within a bore 31 of sleeve element 27, and has a flange 32. A helical compression spring 33 is disposed between flange 32 and the top of sleeve element 27. A convex nose 34 is provided at the end of plunger element 28 engageable with central portion 18 of closure plug 11, this nose having a con vexity greater than the corresponding concavity of zone In operation, the parts will be assembled as shown in FIGURE 2, and plunger 28 forced downwardly, exerting an axial force at the center of plug 11. This will cause a deformation of the disc curvature so that the disc may be inserted into bore 15. More particularly, the increase in curvature of inner zone 18 caused by the axial force will contract the periphery of closure plug 11, and surface portion 23 will slide downwardly through flared entrance 17 into bore 15. Release of force on plunger 28 will permit plug 11 to exert a radially outward force on bore 15 due to its resiliency and the fact that it is held in contracted position by the bore as shown in dot-dash lines in FIGURE 2. This will cause edge to bite into the bore wall or to be blunted slightly thereagainst, thus sealing the bore interior. Any pressure exerted from within the bore on plug 11 will tend to expand it, since it will act on the convex surface of central zone 18, this zone being substantially larger than zones 19 and 21.

An important advantage of the invention is the fact that it does not require a machined outer edge but utilizes one of the edges connected by edge surface portion 23 to bite into the bore wall. In previous expansible closure plug constructions using the principle of initial contraction by exertion of tool pressure, the edge of the plug has had to receive a special machining operation in order to provide a sealing edge of suflicient strength to resist its substantial deformation when the plug is inserted in the bore and is later forced out against the bore wall.

An example of such a previous construction is found in Patent No. 2,687,228 issued August 24, 1954, to the present applicant. A problem with such previous constructions was that their edges had to be machined, since an insufficient included angle at the biting or sealing edge would permit this edge to be deformed during installation or use. With the present invention, the closure plugs may be fabricated by a simple stamping operation from a punched or stamped flat blank as shown in dot-dash lines in FIGURE 1 but without machining, thus greatly decreasing the cost of the plugs, especially when large quantities are produced for mass production installations such as in automobiles. In the stamping operation, edge surface portion 23 may be formed at substantially right angles to the inwardly and outwardly facing plug surfaces, and the plug then formed into its desired shape as shown in the various embodiments.

FIGURE 3 shows another embodiment of the closure plug, generally indicated at 101. This embodiment is similar to closure plug 11 except that in its unstressed condition outer edge 102 of inwardly directed surface 103 is approximately in the same plane as the central portion of surface 103, whereas in closure plug 11, edge 24 was below the level of the central portion of surface 12. Closure 101 may be fabricated in the same manner as closure plug 11 and is insertable by a tool similar to 4 tool 26. In its installed position it will occupy the dotdash line position shown in FIGURE 3.

FIGURE 4 shows another type of assembly tool generally indicated at 201, this tool being illustrated in conjunction with a closure plug 101. Tool 201 has a sleeve element 202 with a lower annular surface 203 engageable with part 204 surrounding flared entrance 205 thereof, this flared entrance being for bore 206 in part 204. A recess 207 in sleeve 202 surrounds plug 101 in its unstressed condition, and a plunger element 208 is slidably mounted within sleeve 202. Plunger 208 has an adjustable step 209 for determining the depth to which the plunger may be inserted in bore 206, thus in turn determining the location of plug 101 as shown in dot-dash lines. A nose 211 is provided on plunger 208 engageable with plug 101. The portion 212 of plunger 208 extending from nose 211 has substantially the same diameter as bore 206 except for slight clearance, a shoulder 213 at the upper end of surface 212 being engageable with sleeve 202 to limit the upper position of the plunger. Tool 201 may be aligned with respect to bore 206 by inserting plunger portion 212 in bore 206 before plug 101 is placed in its initial position. Plunger 208 may then be raised and plug 101 inserted in a slot 214 in sleeve 202, dropping into engagement with flared entrance 205.

Alternatively, plug 101 may be used to centralize plunger 208 with respect to bore 206. This may be done by forming the plug so that it projects slightly above the surface of part 204, and then placing sleeve 202 over the plug. As another alternative, plunger element 208 may be made of magnetic material, and plug 101 mounted on it, the assembly comprising tool 201 and plug 101 then being placed over flared entrance 205.

FIGURE 5 shows a still further embodiment of an assembly tool generally indicated at 301. In this case flared entrance 302 is formed as part of sleeve element 303 of tool 301. Plunger 304 has a portion 305 of substantially the same diameter as bore 306 and is insertable therein before plug 101 is placed in position.

FIGURE 6 illustrates another embodiment of the closure plug generally indicated at 401. This embodiment is the same as that shown in FIGURES 1 and 3 except that central zone 402 of plug 401 is fiat instead of concave toward the bore. The action will be the same, however, since application of an axial force to the center of zone 402 toward the interior of bore 403 will cause con-traction of plug 401 and sliding of edge surface portion 404 through flared entrance 405, the plug having a final position as shown in dot-dash lines in FIGURE 6 with zone 402 slightly convex toward the bore interior.

FIGURE 7 shows a still further embodiment of the closure plug generally indicated at 501. This embodiment is quite similar to those of FIGURES l and 3 except that in its unstressed condition outer edge 502 .of inwardly facing surface 503 is higher than the center of surface 503. The action of the plug will be the same, however, the plug occupying the final position shown in dot-dash lines in FIGURE 7.

FIGURE 8 shows still another embodiment of the invention of the closure plug, generally indicated at 601, which differs from the previously described embodiments of the closure plug in that a peripheral portion of inwardly directed surface 602 has approximately the same angle as flared entrance 603 and is engageable therewith in the unstressed position of the closure plug. Plug 6011 has a central zone 604, an intermediate zone 605 surrounding the central z-one and an outer zone 606 surrounding zone 60'5. As in the previous embodiments, central zone 604 lies entirely on one side of an imaginary plane, indicated in dot-dash lines at 607, which intersects outwardly facing surface 608 at the juncture of zones 604 and 605. Unlike the previous embodiments, however, intermediate zone 605 is convex rather than concave toward the interior of bore 609.

Inwardly facing surface 602 has a portion in outer zone 606, and outer zone 606 is inclined so that surface portion 611 has about the same angle and engageable with flared entrance 603 when the plug is unstressed. As in the previous embodiments, an edge surface portion 612 of plug 601 connects the outer edges 613 and 614 of surfaces 602 and 608, respectively, being preferably at right angles to these surfaces at edges 613 and 614. Because of the inclination of zone 606, edge 613 is of a larger diameter than edge 614. Edge 613 is relatively sharp and has an included angle sufficiently large to prevent substantial deformation thereof when plug 601 is inserted in bore 609.

The insertion will be accomplished by an axial force exerted by a tool plunger shown partially in dot-dash lines at 615 on the center of surface 608 toward the bore interior, thus causing contraction of plug 601 and sliding of surface 611 through entrance 603 into the bore, as shown in dot-dash lines. In the installed position, the stressed nature of plug 601 will cause edge 613 .to bite into the bore wall or be blunted slightly thereagainst, providing circumferential contact with the bore. Any pressure within the bore will be exerted main-1y on central zone 604, tending to expand the plug further and enhance the sealing action.

FIGURE 9 shows a further embodiment of the closure plug, generally indicated at 701, which is similar to that of FIGURE 8 except that central zone 702 is initially flat instead of convex toward the bore interior. Here again, an axial force exterted on the plug will cause contraction of the outer diameter, facilitating entry into bore 703. In its final position, as shown in dot-dash lines, zone 702 will have a slight convexity toward the bore interior so that pressure within the bore will tend to expand the plug against the bore wall.

FIGURES 10 and 11 illustrate another embodiment of the closure plug of the present invention and another type of tool for assembling the same into a workpiece. More particularly, FIGURE 10 illustrates a closure plug 800 that has a central inner zone 801, an inner zone 802 surrounding the central zone 801 and occupying the major part of the plug 800, an intermediate zone 803 surrounding zone 802, and an outer zone 804 surrounding zone 803. The central zone 801 defines an upwardly extending locating projection 805 that is concave downward and functions in a manner later to be described. As in the hereinbefore described embodiments of the present invention, the inner zone 802 lies on the lower side of an imaginary plane intersecting the upwardly facing surface portion 806 of the plug 800 at the juncture of the inner and intermediate zones 802 and 803, re-

spectively. An edge surface portion 807 is provided between the outer edge 808 of a downwardly facing surface 809 and an outer edge 810 of the upwardly facing surface 806, the surface portion 807 extending continuously between the edges 808 and 810. The outer zone 804 is inclined slightly in a manner such that the surface portion 807 is a approximately the same angle as a flared entrance 811 of a bore 812 which is formed in a typical workpiece 813 (see FIGURE 11). The diameter of the plug 800 in its unstressed condition is such that the surface portion 807 is matingly engageable with the flared entrance 811 and accordingly the outer edge 810 of the upper surface 806 is larger in diameter than the outer edge 808 of surface 809.

Referring to FIGURE 11, it will be seen that the bore 812 is formed with a counterbore 814 which is slightly larger in diameter than the bore 812 and the outer adge 810 of the plug 800 to enable the plug 800 to be easily slidably inserted therewithin. The counterbore 814 is substantially the same diameter as and terminates at the upper and radially outermost portion of the flared entrance 811, the counterbore 814 being adapted to act as a guide means for initially positioning the plug 800 at the outer end of the bore 812, thereby providing for rapid assembly of the plug 800. The counterbore 814 will be particularly useful for initially locating the plug 800 when the same is to be assembled in the field.

The closure plug 800 is adapted to be operatively inserted within the bore 812 by means of a tool, generally designated 815, which comprises a plug engaging head section 816 and a cylindrical shank section 817, the latter of which is preferably supported for vertical reciprocal movement by any suitable means such as a sleeve element (not shown) similar to the aforedescribed element 27. The head section 816 is formed with a lower convex face portion 818 which is engageable with the inner zone 802 of the plug 800. An upwardly extending annular centering recess or bore 819 is formed at the center of the face portion 818 and is adapted to receive the upwardly extending locating projection 805 as the tool surface 818 is engaged with the upper surface 806 of the plug 800. It will be seen that as the locating projection 805 is inserted into the recess 819, the tool 815 will be automatically centered with respect to the plug 800 so that a downwardly exerted force on the tool 815 will be automatically applied to the center of the closure plug 800, thereby assuring that the plug 800 will be uniformly and evenly inserted into the bore 812. As the plug 800 is forced downward toward the lower end of the flared entrance 811, the plug 800 will deform slightly in the above-described manner, whereby the inner zone 802 will tend to contract the periphery of the plug 800 so that the surface portion 807 will slide downwardly through the flared entrance 811 into the bore 812. When the force exerted on the tool 815 is relieved, the plug 800 will exert a radially outwardly directed force on the bore 812 due to its natural resiliency. This will cause the edge 810 to bite into the wall of the bore 812 to provide a fluid-tight seal therein.

While it will be apparent that the preferred embodiments of the invention disclosed are will calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. A closure plug for an opening adapted to be provided with an outwardly flared entrance, said closure plug comprising a unitary circular member fabricated of resilient material and having a continuous inwardly facing surface adapted to face the interior of said opening and a continuous outwardly facing surface adapted to face said entrance when said plug is installed, both of said surfaces being smooth unribbed surfaces of revolution, said member having a central inner zone, an intermediate zone surrounding said inner zone, and an outer zone surrounding said intermediate zone, said inner zone being entirely on the side toward the interior of said opening of an imaginary radial plane intersecting said outwardly facing surface at the juncture of said inner and intermediate zones, said inwardly facing surface having an annular portion in said outer zone, an annular edge surface portion extending continuously between and connecting the outer edges of said inwardly and outwardly facing surfaces, said outer zone being so inclined that one of said two last-mentioned annular surface portions has substantially the same inclination as and is adapted to engage a substantial area of said flared entrance when said plug is disposed at said entrance, said intermediate zone being curved to connect said inner and said outer zones in a continuous manner, whereby pressure applied to the center of said plug in a direction toward the interior of said opening when said plug is disposed at said entrance will cause contraction of said outer zone, said contraction being equal and unvarying around the entire periphery of said outer zone due to the smooth unribbed nature of said inwardly and outwardly facing surfaces, and will also cause sliding of said one surface portion through said flared entrance into said opening, and engagement of one of said two outer edges with the wall of said opening, said one outer edge being relatively sharp and having an included angle sufficiently great to prevent substantial deformation thereof by engagement with said opening wall, the radially outward force with which said one outer edge engages said opening wall being equal and unvarying around the entire periphery of said one outer edge due to the smooth unribbed nature of said inwardly and outwardly facing surfaces.

2. The invention as set forth in claim 1 wherein said closure plug is formed with a central inner zone surrounded by said inner zone, said central inner zone defining a locating projection extending above said imaginary plane and adapted to centrally position a tool used to insert said plug into a workpiece.

3. The invention as set forth in claim 1 wherein the diameter of the outer periphery of said closure plug is small enough to be easily slidably inserted within a counterbore that is located at one end of the opening and is of substantially the same diameter as the radially outermost portion of said flared entrance.

No references cited.

THERON E. CONDON, Primary Examiner.

G. T. HALL, Assistant Examiner. 

1. A CLOSURE PLUG FOR AN OPENING ADAPTED TO BE PROVIDED WITH AN OUTWARDLY FLARED ENTRANCE, SAID CLOSURE PLUG COMPRISING A UNITARY CIRCULAR MEMBER FABRICATED OF RESILIENT MATERIAL AND HAVING A CONTINUOUS INWARDLY FACING SURFACE ADAPTED TO FACE THE INTERIOR OF SAID OPENING AND A CONTINUOUS OUTWARDLY FACING SURFACE ADAPTED TO FACE SAID ENTRANCE WHEN SAID PLUG IS INSTALLED, BOTH OF SAID SURFACES BEING SMOOTH UNRIBBED SURFACES OF REVOLUTION, SAID MEMBER HAVING A CENTRAL INNER ZONE, AN INTERMEDIATE ZONE SURROUNDING SAID INNER ZONE, AND AN OUTER ZONE SURROUNDING SAID INTERMEDIATE ZONE, SAID INNER ZONE BEING ENTIRELY ON THE SIDE TOWARD THE INTERIOR OF SAID OPENING OF AN IMAGINARY RADIAL PLANE INTERSECTING SAID OUTWARDLY FACING SURFACE AT THE JUNCTURE OF SAID INNER AND INTERMEDIATE ZONES, SAID INWARDLY FACING SURFACE HAVING AN ANNULAR PORTION IN SAID OUTER ZONE, AN ANNULAR EDGE SURFACE PORTION EXTENDING CONTINUOUSLY BETWEEN AND CONNECTING THE OUTER EDGES OF SAID INWARDLY AND OUTWARDLY FACING SURFACES, SAID OUTER ZONE BEING SO INCLINED THAT ONE OF SAID TWO LAST-MENTIONED ANNULAR SURFACE PORTIONS HAS SUBSTANTIALLY THE SAME INCLINATION AS AND IS ADAPTED TO ENGAGE A SUBSTANTIAL AREA OF SAID FLARED ENTRANCE WHEN SAID PLUG IS DISPOSED AT SAID ENTRANCE, SAID INTERMEDIATE ZONE BEING CURVED TO CONNECT SAID INNER AND SAID OUTER ZONES IN A CONTINUOUS MANNER, WHEREBY PRESSURE APPLIED TO THE CENTER OF SAID PLUG IN A DIRECTION TOWARD THE INTERIOR OF SAID OPENING WHEN SAID PLUG IS DISPOSED AT SAID ENTRANCE WILL CAUSE CONTRACTION OF SAID OUTER ZONE, SAID CONTRACTION BEING EQUAL AND UNVARYING AROUND THE ENTIRE PERIPHERY OF SAID OUTER ZONE DUE TO THE SMOOTH UNRIBBED NATURE OF SAID INWARDLY AND OUTWARDLY FACING SURFACES, AND WILL ALSO CAUSE SLIDING OF SAID ONE SURFACE PORTION THROUGH SAID FLARED ENTRANCE INTO SAID OPENING, AND ENGAGEMENT OF ONE OF SAID TWO OUTER EDGES WITH THE WALL OF SAID OPENING, SAID ONE OUTER EDGE BEING RELATIVELY SHARP AND HAVING AN INCLUDED ANGLE SUFFICIENTLY GREAT TO PREVENT SUBSTANTIAL DEFORMATION THEREOF BY ENGAGEMENT WITH SAID OPENING WALL, THE RADIALLY OUTWARD FORCE WITH WHICH SAID ONE OUTER EDGE ENGAGES SAID OPENING WALL BEING EQUAL AND UNVARYING AROUND THE ENTIRE PERIPHERY OF SAID ONE OUTER EDGE DUE TO THE SMOOTH UNRIBBED NATURE OF SAID INWARDLY AND OUTWARDLY FACING SURFACES. 